In the last entry you saw me preparing roadtrip directions. Rally racing drivers need to prepare directions too, with each step containing way more information than us civilians need. For one thing, they're operating in three dimensions, being as concerned with road pitch and angle as they are with directionality.
Actually, strike that—they're operating in four dimensions: At the breakneck speeds at which they travel, they need to factor in time and pre-calculate which way the car ought to be drifting—leftwards, for example—when they hit a particular berm and leave the ground, so that the leftward momentum will bring them back down safely onto the road at the end of that step.
Obviously a rally driver cannot afford to take his eyes off of the road, so a navigator rides shotgun to call out the "plays," as it were. They carry what are known as "pacenotes" in place of what we'd call directions.
If I screw my directions up, I go five miles out of my way and lose ten minutes. If rally drivers screw their directions up, they go five feet out of their way and lose their lives over the side of a cliff. Because of this, they need to record a lot of information in each step, which can be a combination of little sketches, icons and/or rally driver shorthand letters and numbers. For example, what would be a mere left turn to you or I, to a rally driver might be a decreasing-radius downhill left-hander. The navigator must communicate this to the driver more quickly than that would take to say, so they develop a verbal shorthand.
As you can see in the variety of pacenotes below, there's no established standard for how they ought to be drawn; it largely depends on the artistic and organizational tastes of the drawer or whatever graphics program they're using.
As for who's drawing them, that's the responsibility of the navigator, who's also called the co-driver. In the video below you can see the popular motorsports competitor Travis Pastrana pre-driving a rally course with his co-driver as they work out the notes. You can also get a sense, as they tackle the course full-speed in the second half, how crucially important the pacenotes are. It is literally the difference between life and death.
In the video you overhear them working out some of their own slang as they "recce," or perform reconnaissance, on the course. But some rally organizations forbid recon, and instead provide each team with pre-drawn pacenotes produced in a computer program.
It's not only rally drivers who use pacenotes. Mountain bikers use them too, and websites like this one from Belgium provide freely downloadable pacenotes for popular courses. As you can see below, they look like worksheets for learning some exotic foreign script:
Motorcyclists, too, use pacenotes. But obviously you don't have the option, on two wheels, of having a co-driver; so how the heck do they access them? We'll take a look at that next.